Recording pressure-gage.



E. H. BRISTOL. RECORDING PRESSURE GAGE. APPLICATION FILED APR. 12, 1906.

Patented Aug. 9, 1910.

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RECORDING PELESSURE GAGE.

APPLICATION FILED APILIZ, 1906.

Patented Aug. 9,1910.

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UNITED STATES PATENT OFFICE.

EDGAR rr. BRISTOL, or uauca'rucx, connnc'rrcu'r, assreuon ro THErunus'ramr'.

INSTRUMENT COMPANY, or warnanumr, connncrrcurr, a coarona'rron or con-NECTICUT.

seonoo.

To all whom it may concern:

Be it known that I, EDGAR BRISTOL, a

I citizen of the United States, residing at ,Naugatuck, in the county ofNew Haven,

State of Connecticut, have invented an Improvement in RecordingPressure-Gages, of which the following description, in connection withthe accompanying drawings, isa

specification, like. characters on thedra-wings representing like parts.

My invention relates to devices for indicating and 1 recording pressuresor variations thereof and more particularly to a type of instrumentcomprising an expansion tubemade up of expanslble sections,

one end of said tube bein a secured while the tube is provided with aflat strip of metal suitably secured thereto while permittin theelongation of the opposite unrestrain side, thereby producing aresultant deflection of the free end of the tube andof the pointercarried thereby, the movement of which relative to the graduations ofthe chart is utilized to indicatethe pressure.

In instruments of this type, as hitherto con-..

structed, the restraining strip has been a flat metal band secured tothe strip by solder necessarily applied on its inner side next to.

the tube. The solder being'applied as described is found tointerferewlth the resiliency of the strip and to impair the efiicient. actionthereof and consequently of sald tube so that'after it has'beendeflected a number of times itacquires a slight permanent deflectiontechnically called a set and, while.

easily deflected under varying pressures, a

return to normal position under normal pressure 1s not read ly obtalned.

One of the aims of my invention is to overcome this objection and at thesame time provide a sensitive instrument that will indicate and recordall variations "of pressure without appreciableierror. This. and otherfeatures of my invention, however, Willbe best understood and morethoroughly appreciated from the following description when taken inconnection with the accompanying drawings of. an instrumentembodying'one form of my invention, its scope be- Specification ofLetters Patent. Application filed April 12, 1906. Serial No. 311,255.

imconnme PRESSURE-GAGE.

Patented Au 9, 1910.

ing more articularly pointed out in the appended c aims. i

Referring to the drawings,Figure1 is a front elevation of a completeinstrument selected for (purposes of illustration; Fig. 2,

anenlarge sectional detail of the lower end of the expansion tube, toshow the manner of securing the flexible restraining coil thereto; Fig.3, an enlar ed detail in elevation of the right side of tgeupper end ofthe expansion tube, to show th'e restraining coil, the adjustableinkingpointerfand the means for attaching it to said tube; Fig. 4,"anen'- larged sectionaldetail ofthe coil and the adjacent edge of the diahragm connected therewith, taken on the inc-H, Fig. 3; Fig. 5, a plan ofa modification in which two coils are used; Fig. 6', a front elevationof the top thereof, the lower part of the coil heing omitted; Fig. 7, anelevation'of a differential ga e or recorder in which a m0dified form 0tube is used; Fig. 8,a vertical sectional detail of one of the tubes, toshow the parallel corrugations; Fig. 9, a similar view of a modificationin which the concentric corrugations of adjacent sections inter .lock;Fi 10, a vertical section on line 1010, F1g. 7, with parts broken awayto show the attaching end of the pointer of pen arm; and Fig. 11 is aplanof a detail on a somewhat smaller scale, showing a di erentialpressure tube employing a plurality of restraining coils. V y.

In theembodiment of my invention illustrated the instrument comprises asuitable case, 1, to receive the pressure recording .me chanism composedof a chart 2, rotatabl secured upon the central spindle of. a cloci orclockwork (not shown), the pressure expansion tube 3, and its inkingpointer or pen arm 4. :At its lower end the tube 3 has a head 5 (Figs. 1and 2), provided withsecuring means to suipportit in an upright positionwithin sai case, said hea opening therethrough and a nipple 6,- com-..municatiugtherewith and receiving the pipe having an a 7, which isconnected to any fluid containing receptacle, the pressure of which'isto beindicated or recorded. As'herein shown. (see Fig. 2)v theexpansiontube comprises a plurallty of expansible diahragm. sections 8,each-formed of two cireu ar corrugated dia phragms or disks 9,'eachirovided with a central opening 11. The e es of these diaphragmsare suitably united to form a series button 12, the lower section formedwith or united to the head 5, the opening 11 com-' the restraining means.employe of ex ansion chambers 10, each communicating' w1th the othersthrough the central openings 11, and constituting together a continuoustube.' A suitable number of sections having been united in this way theupper opening in the tube is closed by a cap or municating therewith andwith that of said nipple 6, and the pipe 7.

Instead of ,using the usual flat metallic strip for restraining theelongation of one side of .the'tube while the opposite side is free toelongate to producethe desired deflection, I have found it advantageousto provide restraining means having curved having a shallow recess orgroove 15, in

- said grooves being cut transversel which the adjacent edge of thediaphragm section 8, is suitably secured, as by solder; or at rightangles to the length of the co' in that I portion of each convolutionadjacent the .tube. The metal of which said'coil 13', is. 40

made is preferably the same as that of the tube '3, or at least one{having approximately the same coefficientof expansion through the usualrange .of temperature to which the tube may be subjected, so that its.deflections will be uniform for the same dif-.

ferences or changes of pressure. The convolutions of said coil sprmg 13,when not sub- "and resiliency are secure jected'to external forces arenormally separated a distance equal to that between the edges of thediaphragm sections, so that said coil and the tube connected therewithwill normally be vertical.

7 By using a coil spring eater durability than is ossible with a" fiatstrip and sulficient lengt of -resilient metal is inter osed between thesectionsof the tube to glve the effect of spring hinges, enabling. oneto: be pivotally connected with another, furnishlng additionalelasticity to the expansion tube to cause or permit it always to returnto normal position, when the-pressure which caused adeflectionthereofreturns to the normal, there 'bein no tendency towarda-per'manent deflection onset of the tube or therestraininlg 13 islongitudinally arranged alongone side of the expansion tube, the outersurface of each convolution 14 of the coil coil, the'responsiveness ofthe tube or strip notbeing limited in any way.

By arranging a plurality of connections,

like coils 13?, in the present instance, shown asextending continuouslyfrom top to bottom at one side of the tube, a more perfect alance andaction is obtained than would be the case if a single rest-rainingspring or coil were used, but my invention of course is not limited inthis respect. When two coils 13 are used, they may each be made lighterand smaller than the single' coil 13, and they are preferabl arranged atright angles to the planes 0 the diaphragms or parallel with the lengthof the tube, said spring being of similar construction to spring 13except that the peripheries of the convo-' lutionsare directly securedto those of the diaphragms, .the recesses in the surfaces of theconvolutions bein omitted. These coils also act as spring hinges betweenthe sections of the tube and have a tendency to limit the deflection ofthe tube to a vertical plane a,a, Fig. 5, parallel with the face of thechart 2, and passing through the axis of the tube, the axes of the coilsprings being equally distant from said plane to secure such effect.These coils 13, 13 each present curved metallic elements between thesections which are not only flexible but are also expansible andcontractible in the direction of their length but are made stiff enoughto yield less readily in that direction than the'tube, so that in theexpansion of the tube their natural tension restrains the elongation ofone side of the tube to produce a deflection thereof as described.

Ino eration any variation between the externa pressure and that withinthe tube causes a contraction or expansion of the several sectionsandconsequently of said tube in the direction of its length. As elongationat one side of the tube is restrained by the coil spring 13', or by thecoil springs 13 the elongation of the opposite unrestrained side causesthe upper or .free end of the tube to deflect toward or from therestrained side of the tube and this movement is utilized to indicateand record the pressure to which said deflection is due, an inkingpointer or pen arm 4 being provided, and

carried by the free end of the tube, its

proper position being at the front of the tube so thatit will bedeflected in the plane of the chart as described. While any de-.

siredtype-of inking pointer'may be used, that herein shown comprises anadjustable spring clip'. 16, adapted to embrace t 1e edge of one, of thediaphra sections and by which, it is attached t ereto. The upper partofsaid clip '16 is bent inwardly toward the chart, its end having a headedstud 17 secured a longitudinal slot 18 at the lower end of the. inkingpointer, and fitting closely therein to form a well known type offricupper end of said pointer 4 to be placed in any desired positionupon the chart or dial 2.

Fig. 7 represents a differential pressure recorder which has two tubessupported upon-a similar head 5, having two nipples 6, each connected inthe usual manner to.

their respective pressure vessels or receptacles, the restraining meanstherefor inthe present instance comprising a single coil spring 13",though obviously a plurality of such coils, 13*, Fig. 11 may be used andare Within the scope of my'invention. The rims of the sections 8 aresecured to opposite sides of the coil 13*, in the present instance, by

soldering them Within the horizontal grooves 15 cut on the oppositesides of each convo lution. These tubes a'reequally expanded as long asthe pressures remain equal in the pressure receptacles with which theyare connected; but as the pressure of one ex- I ceeds the other, thegreater expansion of its connected ressure tube produces a correspondingeflection of the; tube or tubes through the restralning etl'ect preducedby the coil 13*. As the unrest-rained "outer and opposite rims or edgesof the sections in all tubes of this type, as hitherto constructed,

- tend to separatemore .than the restrained edges, as, pressure isadmitted tothe tubes,

1 instantaneous deflection thereof maynot follow until such separationhas .been effected, Which is not'an advantageous or beneficial effectand shouldbe avoided. I have over come this tendency rigidly connectingthe b 'M" top and bottom of tlie restraining coil with the upper andlower sections of each tube, by. means of strips or 'gplate's,respectively numbered 20 and 21 in the drawings (Figs. 1

and 7-). These strips 20, 21 arepreferably soldered to the ends of thesprin or springs and to to ahd bottom pf the tu or tubes, according yias one or two tubes are employed. These strips effectually] prevent theexpansible sections from separating, fanlike, one from the other, attheir unrestrained sides, except as the coil is deflected, so that thepressures are entirely utilized in producing deflection to move thepointer or inking arm Without any loss of motion. The pointer in thiscase, see Fig. 10, is provided with a usual spring clip, 16, forattachment to the tube, being shaped to embrace the up:

per truss frame or strip 20, and secured thereto in any desirab emanner.- As herein shown, the pen arm has an intermediate section 22,united to the pen! arm pro er by ceived into the loop 24, of the ointer.This tion of the tube behind said chart 2, and using a much shortercasing l which is desirablefsince it cheapens the cost of production andprovides a *more cempact instrument.- For this reason I have devised theforms of expansible sections illustrated by Figs. 8 and 9, the formercomposed of diaphragms 9, each having parallel concentric corrugations9, permitting adjacent sections to be placed nearer, togetherlongitudinally and providing a shorter tube to produce a requireddeflection than Whenfthe sections are not fitted together in thismanner, as in .the usual type of tube 3 (Fig. 1). In the otherform (Fig.9), the concentric corrugations of each diaphragm occupy a difi'er entposition radially-to that occupied by those of the adjacent sect-ions sothat said sections may be placed relatively closely together, as shownin FigI-Q, the convex faces 9 otl one fitting withithe concavedcpressions 9 of the ad acent sections and vice versa. In each of theseforms, the sect-ions may be said to interlock one with the other,thereby producing a much shorter tube than those in commonuse, theremaining details of construction being similar those already described;I

The differential gage or recorder (Fig. 7 operates upon the sameprinciple and in the same manner as the single tube With'this exception; that while the single tube operates as soon as a difference ofpressure exists betrveen the outerand inner surfaces thereof, thedifferentialg'equires in additionthereto, a* difference between thepressures to which each tube is subjected. Obviously, as long as thepressures to which the tubes are subjectedremain equal, each tube isexpanded equally and the restraining coil is equally affected thereby,so that no deflection is produced, but as the pressure of one tube V3,?ries from the other, the tube subjected to i the greater internalpressure will be exl panded more than the other, causing its deflectionand the resulting deflection of the i; restraining coil and the tively'corresponding to pressures and hours inking material and traces a lineupon the chart corresponding to the varying pressure within the tube 6,pipe 7-, and vessel to which the latter is connected, said line beingeontimious and. constituting a complete record of the pressure and itsfiuctuations for the twenty-four'hours or day,

The instruments herein described :and illustrated are adapted for usewherever ressures are .to be indicatedor recorded; it

eing equally immaterial whether they are of the day? The pen 19 carriessuitable,

cator of a pressure tube &

used for or withsteam, gas, air, or other fluid, or whether usedjtorecord pressures above that of the atmosphere or for vacuums.

They are also equally adapted to record changes in external pressure bymaintaining the internal pressure constant.

While in the. embodiment illustrated. I have shown coils or springsextending from top to bottom of the tube and operating in the samemanner as the springs 13 or 13, it .is

'obvious that my invention is not limited to the specific embodiment,its details of con struction or arrangement of parts herein selected forpurposes of illustration only, but

that the same may be suitably modified within wide limits withoutdeparting from the spirit and scope thereof.

Claims: 1. The combination in a pressure indicator of a pressure tubeprovided with a series of expansible sections, restraining meanstherefor, comprising a curved attaching, element extending from top tobottom of the tubeand connected with a plurality of said sections, anarm connected with said tube forthe purpose described.

' 2.. The combination in, a pressure indirovided with a series ofexpansible sections, restraining means therefor comprising an attachingele-' ment curved transversely-relative to the'axis of the tube andconnected with a plurality of said sections. 1 j

3. In a pressure indicator, an expansion tube provided with a series "ofexpansible sections and restraining means therefor comprising aplurality of. curved attaching elements arranged longitudinally at oneside of said tube and connected with a plurality of said sections.

4. In a pressure indicator, an expansion tube provided with a se-rles ofexpansible sections and means for restraining the elongation of one sideof the tube, said.

exceeding the distance between the latter.

6. A differential pressure gage comprising a lurality of pressure tubeshaving means or connection with different pressure receptacles andrestraining means interposed etween and connected with the opposing andadjacent portions of said tubes and arranged longitudinally thereon toproduce simultaneous deflect-ion thereof upon variation in the pressureto which said tubes are subjected.

7. In a difierential pressure gage, a plurality of pressure tubes eachcomprising a series of expansible sections, and restrainln meansinterposed between and connecte with the opposing or adjacent edges of aplurality of the sections of each tube and comprising a devicepresenting a length of metal between its points of connection with eachof said tubes greater than the distance between said points forproducing a simultaneous deflection of saidtubes.

8. A pressure tube comprising a series of expansible diaphragm sections,a restraining device arrangedvat one side of said tube, and truss meansconnecting the central portions of said tube with said device to preventseparation of said sections atthe unrestrained sides or edges thereofand for causing simultaneous deflections of said tube and said device.

'9. A pressure tube comprising a series of expansible sections, arestraining device arranged at one side of said tube and rigidconnections comprising the bars 20 and 21 between said device andsections to prevent separation of the tube sections adjacent theirunrestrained edges without producing simultaneous deflection of saiddevice and said tube.

'10. A pressure tube comprising a series of expansible sections, eachhaving a corrugated surface, the corrugations of one section fitting thecorrugations of adjacent sections thereof, permitting the sections to bearranged close together.-

11. A pressure tube comprising a series of expansible diaphragm sectionseach composed of diaphragms provided with concentric corrugations, theelevations and depressions of the diaphragms of one section occupyin adifferent peripheral position from those 0 the adjacent sections topermit said sections tobe placed close together.

12. In a pressure indicator, the tube 3 provided with expansiblesections 8 and one or more restraining coils 13 connected with the edgesof a plurality of said sections.

1'3. In a'pressure indicator, a series of connected expansible sectionsforming a continous tube and a restraining device for one side of andconnected with a plurality of said.sections having a length, between itspoints of attachment, greater than the distance between said points.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribin witnesses.

- GAR H. BRISTOL.

Witnesses:

ROBERT H. KAMMLER,-

SIDNEY F. SMITH.

